TIDUF55 November   2023

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Power Tree and Wakeup
      2. 2.2.2 Insulation Requirement for Isolated Interface
      3. 2.2.3 Robust Relay Driver
      4. 2.2.4 Stackable Daisy Chain Communication
    3. 2.3 Highlighted Products
      1. 2.3.1  TMDSCNCD263
      2. 2.3.2  LMR51440
      3. 2.3.3  TPS7A16
      4. 2.3.4  TPS7B81
      5. 2.3.5  TPS62913
      6. 2.3.6  TPS4H160-Q1
      7. 2.3.7  ULN2803C
      8. 2.3.8  ISO1042
      9. 2.3.9  UCC12050
      10. 2.3.10 ISO1410
      11. 2.3.11 SN6505B
      12. 2.3.12 BQ32002
      13. 2.3.13 HDC3020
      14. 2.3.14 TPS3823
      15. 2.3.15 DP83826E
      16. 2.3.16 TPS763
      17. 2.3.17 LM74701-Q1
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software Requirements
    3. 3.3 Test Setup
    4. 3.4 Test Results
      1. 3.4.1 Power Supply Testing
      2. 3.4.2 Daisy Chain Signal Quality
      3. 3.4.3 Relay Driving
      4. 3.4.4 Isolated CAN Transceiver Operation
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

2.3.17 LM74701-Q1

The LM74701-Q1 is an automotive AEC Q100 qualified ideal diode controller which operates in conjunction with an external N-channel metal-oxide semiconductor field-effect transistor (MOSFET) as an ideal diode for low loss reverse polarity protection with a 20-mV forward voltage drop. LM74701-Q1 is an excellent choice for input protection of 12-V automotive systems. The 3.2-V input voltage support is particularly well designed for severe cold crank requirements in automotive systems.

The device controls the GATE of the MOSFET to regulate the forward voltage drop at 20 mV. The regulation scheme enables graceful turn-off of the MOSFET during a reverse current event and provides zero DC reverse current flow. Fast response (< 0.75 µs) to reverse current blocking makes the device an excellent choice for systems with output voltage holdup requirements during ISO7637 pulse testing as well as power fail and input micro-short conditions. The LM74701-Q1 has a unique integrated VDS clamp feature which enables users to achieve TVS-less input polarity protection design and save, on average, a typical 60% of PCB space in constrained automotive systems.

The LM74701-Q1 controller provides a charge pump gate drive for an external N-channel MOSFET. With the enable pin low, the controller is off and draws approximately 1 µA of current.